//! `aura new` — scaffold a data-only research project (#241).
//!
//! `aura new` emits the data-only tier: a paths-only `Aura.toml`, a runnable
//! starter blueprint over the std vocabulary, `.gitignore`, and `CLAUDE.md` —
//! no crate, no build step. The scaffolder never builds and never loads (the
//! project-load phase in `main()` sees a plain data-only project just like
//! any other).
//!
//! The crate-scaffold templates (`ScaffoldSpec`/`scaffold_node_crate`/
//! `scaffold_spec`, cycle 0103, C16/C17) serve the native-node tier: `aura
//! nodes new` attaches a node crate beside a project.
//!
//! Templates are raw strings with `__NS__` / `__NAME__` / `__NAME_SNAKE__` /
//! `__ENGINE__` tokens substituted by plain `.replace()` — no format-string
//! brace escaping in Rust template bodies.

use std::path::{Path, PathBuf};

#[derive(Debug)]
pub struct ScaffoldSpec {
    pub name: String,
    pub namespace: String,
    pub engine_root: PathBuf,
    pub target_dir: PathBuf,
}

fn valid_name(s: &str) -> bool {
    !s.is_empty()
        && !s.starts_with(|c: char| c.is_ascii_digit())
        && s.chars().all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
}

fn valid_namespace(s: &str) -> bool {
    !s.is_empty()
        && !s.starts_with(|c: char| c.is_ascii_digit())
        && s.chars().all(|c| c.is_ascii_alphanumeric() || c == '_')
}

/// The name→namespace / name→blueprint-name mapping: dashes become
/// underscores (mirrors cargo's crate-name normalization).
pub fn snake(name: &str) -> String {
    name.replace('-', "_")
}

/// The compile-time default engine root: two ancestors above aura-cli's
/// manifest dir (`<root>/crates/aura-cli` → `<root>`). Valid on the box the
/// binary was built on; `scaffold_node_crate` refuses when it no longer
/// exists.
pub fn default_engine_root() -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR"))
        .ancestors()
        .nth(2)
        .expect("aura-cli manifest dir has two ancestors")
        .to_path_buf()
}

/// The data-only project scaffold (#241): no crate, no build step.
#[derive(Debug)]
pub struct ProjectScaffoldSpec {
    pub name: String,
    pub target_dir: PathBuf,
}

/// Validate the argv-level inputs for the data-only project scaffold. `Err`
/// is a usage fault — the caller exits 2 (C14 partition).
pub fn project_scaffold_spec(name: &str, cwd: &Path) -> Result<ProjectScaffoldSpec, String> {
    if !valid_name(name) {
        return Err(format!(
            "invalid project name `{name}` (allowed: letters, digits, `_`, `-`; no leading digit)"
        ));
    }
    Ok(ProjectScaffoldSpec { name: name.to_string(), target_dir: cwd.join(name) })
}

/// Validate the argv-level inputs. `Err` is a usage fault — the caller
/// exits 2 (C14 partition).
pub fn scaffold_spec(
    name: &str,
    engine_path: Option<&Path>,
    namespace: Option<&str>,
    cwd: &Path,
) -> Result<ScaffoldSpec, String> {
    if !valid_name(name) {
        return Err(format!(
            "invalid project name `{name}` (allowed: letters, digits, `_`, `-`; no leading digit)"
        ));
    }
    let namespace = match namespace {
        Some(ns) if !valid_namespace(ns) => {
            return Err(format!(
                "invalid namespace `{ns}` (allowed: letters, digits, `_`; no leading digit)"
            ));
        }
        Some(ns) => ns.to_string(),
        None => snake(name),
    };
    Ok(ScaffoldSpec {
        name: name.to_string(),
        namespace,
        engine_root: engine_path
            .map(Path::to_path_buf)
            .unwrap_or_else(default_engine_root),
        target_dir: cwd.join(name),
    })
}

// ---------------------------------------------------------------- templates

const CARGO_TOML: &str = r#"[package]
name = "__NAME__"
version = "0.1.0"
edition = "2024"
publish = false

[lib]
crate-type = ["cdylib"]

[dependencies]
aura-core = { path = "__ENGINE__/crates/aura-core" }

# Standalone workspace root: never a member of an enclosing workspace.
[workspace]
"#;

const AURA_TOML: &str = r#"# Static project context only (C17); paths only.
[paths]
runs = "runs"
# data = "/path/to/archive"  # the recorded-data root; defaults to the built-in path
"#;

const GITIGNORE_CRATE: &str = "/target\nCargo.lock\n";

const LIB_RS: &str = r#"//! __NAME__ — an aura research project: node logic + the exported vocabulary.
//!
//! Every node type this crate provides is registered in `vocabulary()` /
//! `type_ids()` under the `__NS__::` namespace prefix; the `aura` host loads
//! this cdylib per invocation and merges it with the std vocabulary.

use aura_core::{
    Cell, Ctx, FieldSpec, Firing, Node, NodeSchema, ParamSpec, PortSpec, PrimitiveBuilder,
    ScalarKind,
};

/// One-input scalar gain: emits `input * factor`. Emits `None` until its
/// input has a value (warm-up filter, C8).
pub struct Scale {
    factor: f64,
    out: [Cell; 1],
}

impl Scale {
    pub fn new(factor: f64) -> Self {
        Self { factor, out: [Cell::from_f64(0.0)] }
    }
    // Replace `doc` below when renaming this sample node — it must keep
    // describing the node's own behaviour, not this scaffolding step.
    pub fn builder() -> PrimitiveBuilder {
        PrimitiveBuilder::new(
            "__NS__::Scale",
            NodeSchema {
                inputs: vec![PortSpec {
                    kind: ScalarKind::F64,
                    firing: Firing::Any,
                    name: "value".into(),
                }],
                output: vec![FieldSpec { name: "value".into(), kind: ScalarKind::F64 }],
                params: vec![ParamSpec { name: "factor".into(), kind: ScalarKind::F64 }],
                // C29: every vocabulary entry ships a one-line meaning — the
                // doc field is required (E0063 without it) and gated at load.
                doc: "scalar gain: emits the input times the factor param",
            },
            |p| Box::new(Scale::new(p[0].f64())),
        )
    }
}

impl Node for Scale {
    fn lookbacks(&self) -> Vec<usize> {
        vec![1]
    }
    fn eval(&mut self, ctx: Ctx<'_>) -> Option<&[Cell]> {
        let w = ctx.f64_in(0);
        if w.is_empty() {
            return None;
        }
        self.out[0] = Cell::from_f64(w[0] * self.factor);
        Some(&self.out)
    }
    fn label(&self) -> String {
        format!("__NS__::Scale({})", self.factor)
    }
}

fn vocabulary(type_id: &str) -> Option<PrimitiveBuilder> {
    match type_id {
        "__NS__::Scale" => Some(Scale::builder()),
        _ => None,
    }
}

fn type_ids() -> &'static [&'static str] {
    &["__NS__::Scale"]
}

aura_core::aura_project! {
    namespace: "__NS__",
    vocabulary: vocabulary,
    type_ids: type_ids,
}
"#;

const CLAUDE_MD_CRATE: &str = r#"# __NAME__ — an aura node crate

Native node logic for an aura research project (extension-dev role). This
crate is attached to its project via `[nodes]` in the project's `Aura.toml`.

- Build: `cargo build` (the next `aura` invocation in the project loads the
  fresh dylib)
- Each node is registered in `vocabulary()`/`type_ids()` under the
  `__NS__::` namespace prefix; blueprints reference nodes by that id.
- This crate has no data-plane dependencies — nodes are pure stream
  transformers over read-only input windows.
"#;

const GITIGNORE_PROJECT: &str = "/runs\n";

const SIGNAL_JSON_STD: &str = r#"{"format_version":1,"blueprint":{"name":"__NAME_SNAKE___signal","doc":"fast/slow SMA difference clamped into a directional bias","nodes":[{"primitive":{"type":"SMA","name":"fast","bound":[{"pos":0,"name":"length","kind":"I64","value":{"I64":2}}]}},{"primitive":{"type":"SMA","name":"slow","bound":[{"pos":0,"name":"length","kind":"I64","value":{"I64":4}}]}},{"primitive":{"type":"Sub"}},{"primitive":{"type":"Bias","name":"bias","bound":[{"pos":0,"name":"scale","kind":"F64","value":{"F64":0.5}}]}}],"edges":[{"from":0,"to":2,"slot":0,"from_field":0},{"from":1,"to":2,"slot":1,"from_field":0},{"from":2,"to":3,"slot":0,"from_field":0}],"input_roles":[{"name":"price","targets":[{"node":0,"slot":0},{"node":1,"slot":0}],"source":"F64"}],"output":[{"node":3,"field":0,"name":"bias"}]}}"#;

const CLAUDE_MD_PROJECT: &str = r#"# __NAME__ — an aura research project (data-only)

This directory is an aura project: blueprints + research documents over the
std vocabulary, anchored by `Aura.toml`. There is no crate and no build step.

- Run: `aura exec blueprints/signal.json` (single smoke run, synthetic stream
  — the starter is closed; all params bound; bound values are defaults —
  `--override NODE.PARAM=VALUE` may override one for this run (#246))
- Campaign: `aura exec <campaign.json>` executes a registered campaign
  document (file or content id) — the multi-cell/axis surface
- Axes: `aura graph introspect --params blueprints/signal.json` lists the
  open + bound-overridable axes, RAW `<node>.<param>` names (#328)
- Native nodes: when the project needs its first project-specific node,
  `aura nodes new <name>` scaffolds a node crate beside this project and
  attaches it via `[nodes]` in `Aura.toml` (build it with `cargo build`).
- Topology is data (`blueprints/*.json`); results land in `runs/`.
- Execution model: a strategy emits a bias in [-1,+1] per cycle, held as the
  continuously-tracked target position; a protective stop defines the risk
  unit R, and quality metrics are R-based. Entry signals become held state
  via the signal-side latch/edge-pulse idiom (see
  `aura graph introspect --vocabulary`).
- Data plane: the research verbs are sugar over registered process/campaign
  documents — author them directly with `aura process` / `aura campaign`,
  growing one from a bare `{}` via `aura campaign introspect --unwired`.
"#;

/// Render a data-only project template: only `__NAME__`/`__NAME_SNAKE__`
/// tokens exist in this template set (no namespace, no engine path).
fn render_project(template: &str, name: &str) -> String {
    template
        .replace("__NAME_SNAKE__", &snake(name))
        .replace("__NAME__", name)
}

fn render(template: &str, spec: &ScaffoldSpec) -> String {
    template
        .replace("__NAME_SNAKE__", &snake(&spec.name))
        .replace("__NAME__", &spec.name)
        .replace("__NS__", &spec.namespace)
        .replace("__ENGINE__", &spec.engine_root.display().to_string())
}

// --------------------------------------------------------------------- emit

/// Emit a data-only project. `Err` is a runtime refusal (exit 1). All
/// refusals fire before the first write.
pub fn scaffold_project(spec: &ProjectScaffoldSpec) -> Result<(), String> {
    if spec.target_dir.exists() {
        return Err(format!("destination `{}` already exists", spec.target_dir.display()));
    }
    let write = |rel: &str, body: String| -> Result<(), String> {
        let path = spec.target_dir.join(rel);
        if let Some(dir) = path.parent() {
            std::fs::create_dir_all(dir)
                .map_err(|e| format!("creating `{}`: {e}", dir.display()))?;
        }
        std::fs::write(&path, body).map_err(|e| format!("writing `{}`: {e}", path.display()))
    };
    write("Aura.toml", AURA_TOML.to_string())?;
    write(".gitignore", GITIGNORE_PROJECT.to_string())?;
    write("blueprints/signal.json", render_project(SIGNAL_JSON_STD, &spec.name))?;
    write("CLAUDE.md", render_project(CLAUDE_MD_PROJECT, &spec.name))?;
    if inside_git_work_tree(&spec.target_dir) {
        return Ok(());
    }
    match std::process::Command::new("git").arg("init").current_dir(&spec.target_dir).output() {
        Ok(o) if o.status.success() => {
            commit_all(&spec.target_dir, "aura new scaffold");
        }
        _ => crate::diag::warning!("git init failed (project created without a repo)"),
    }
    Ok(())
}

/// Emit a node crate (#241): the native half of the old single-tier scaffold
/// — Cargo.toml + src/lib.rs + crate-scoped .gitignore + CLAUDE.md, no
/// Aura.toml and no blueprints/ (those belong to the research project).
pub fn scaffold_node_crate(spec: &ScaffoldSpec) -> Result<(), String> {
    if spec.target_dir.exists() {
        return Err(format!("destination `{}` already exists", spec.target_dir.display()));
    }
    if !spec.engine_root.join("crates/aura-core").is_dir() {
        return Err(format!(
            "engine checkout not found at `{}` — pass --engine-path <engine checkout>",
            spec.engine_root.display()
        ));
    }
    let write = |rel: &str, body: String| -> Result<(), String> {
        let path = spec.target_dir.join(rel);
        if let Some(dir) = path.parent() {
            std::fs::create_dir_all(dir)
                .map_err(|e| format!("creating `{}`: {e}", dir.display()))?;
        }
        std::fs::write(&path, body).map_err(|e| format!("writing `{}`: {e}", path.display()))
    };
    write("Cargo.toml", render(CARGO_TOML, spec))?;
    write(".gitignore", GITIGNORE_CRATE.to_string())?;
    write("src/lib.rs", render(LIB_RS, spec))?;
    write("CLAUDE.md", render(CLAUDE_MD_CRATE, spec))?;
    // Best-effort git init: a warning, never an error (cargo-new mirror).
    // Also the cargo-new mirror: inside an existing work tree the init is
    // SKIPPED silently — a nested .git is a gitlink/submodule hazard when the
    // scaffold lands in a tracked tree (#204).
    if inside_git_work_tree(&spec.target_dir) {
        return Ok(());
    }
    match std::process::Command::new("git").arg("init").current_dir(&spec.target_dir).output() {
        Ok(o) if o.status.success() => {
            commit_all(&spec.target_dir, "aura nodes new scaffold");
        }
        _ => crate::diag::warning!("git init failed (node crate created without a repo)"),
    }
    Ok(())
}

/// Append the `[nodes]` pointer to a project's Aura.toml. Refuses when a
/// `[nodes]` section already exists (single-crate iteration).
pub fn append_nodes_pointer(project_root: &Path, pointer: &str) -> Result<(), String> {
    let path = project_root.join("Aura.toml");
    let text = std::fs::read_to_string(&path)
        .map_err(|e| format!("reading `{}`: {e}", path.display()))?;
    if text.contains("[nodes]") {
        return Err(
            "Aura.toml already has a [nodes] section (multi-crate loading is not yet supported)"
                .to_string(),
        );
    }
    std::fs::write(&path, format!("{text}\n[nodes]\ncrates = [\"{pointer}\"]\n"))
        .map_err(|e| format!("writing `{}`: {e}", path.display()))
}

/// Stage everything and make the initial commit in a freshly-`git init`ed
/// scaffold, so `git rev-parse HEAD` resolves from the very first run
/// (otherwise HEAD stays unborn and provenance stamping sees no commit). A
/// committer identity is passed inline via `-c` so this works on a box with
/// no global git config; best-effort — a failure is a warning, never fatal,
/// and never runs when `git init` itself was skipped or failed.
fn commit_all(dir: &std::path::Path, message: &str) {
    let add = std::process::Command::new("git")
        .args(["add", "-A"])
        .current_dir(dir)
        .output();
    if !matches!(add, Ok(o) if o.status.success()) {
        crate::diag::warning!("git add failed (scaffold created without an initial commit)");
        return;
    }
    let commit = std::process::Command::new("git")
        .args([
            "-c",
            "user.email=aura@localhost",
            "-c",
            "user.name=aura",
            "commit",
            "-q",
            "-m",
            message,
        ])
        .current_dir(dir)
        .output();
    if !matches!(commit, Ok(o) if o.status.success()) {
        crate::diag::warning!(
            "git commit failed (scaffold created without an initial commit)"
        );
    }
}

/// Whether `dir` already sits inside a git work tree (`git rev-parse`, the
/// same oracle cargo-new consults). A missing git binary or any failure reads
/// as "not in a work tree" — the init stays best-effort either way.
fn inside_git_work_tree(dir: &std::path::Path) -> bool {
    std::process::Command::new("git")
        .args(["rev-parse", "--is-inside-work-tree"])
        .current_dir(dir)
        .output()
        .map(|o| o.status.success() && String::from_utf8_lossy(&o.stdout).trim() == "true")
        .unwrap_or(false)
}

#[cfg(test)]
mod tests {
    use super::*;

    fn spec_for(name: &str, ns: Option<&str>) -> ScaffoldSpec {
        scaffold_spec(name, None, ns, Path::new("/tmp/x")).expect("valid spec")
    }

    #[test]
    fn name_and_namespace_validation_table() {
        assert!(scaffold_spec("ger40-lab", None, None, Path::new("/t")).is_ok());
        assert!(scaffold_spec("x_1", None, None, Path::new("/t")).is_ok());
        for bad in ["", "bad/name", "9lives", "a b", "ä"] {
            let e = scaffold_spec(bad, None, None, Path::new("/t")).unwrap_err();
            assert!(e.contains("invalid project name"), "{bad}: {e}");
        }
        for bad_ns in ["", "with-dash", "9x", "a::b"] {
            let e = scaffold_spec("ok", None, Some(bad_ns), Path::new("/t")).unwrap_err();
            assert!(e.contains("invalid namespace"), "{bad_ns}: {e}");
        }
    }

    #[test]
    fn namespace_defaults_to_snake_name() {
        assert_eq!(spec_for("ger40-lab", None).namespace, "ger40_lab");
        assert_eq!(spec_for("ger40-lab", Some("ger40")).namespace, "ger40");
        assert_eq!(snake("a-b-c"), "a_b_c");
    }

    #[test]
    fn default_engine_root_is_this_checkout() {
        assert!(default_engine_root().join("crates/aura-core").is_dir());
    }

    #[test]
    fn templates_render_without_leftover_tokens() {
        // Crate-template set (native tier, via `ScaffoldSpec`).
        let spec = spec_for("demo-lab", None);
        for t in [CARGO_TOML, GITIGNORE_CRATE, LIB_RS, CLAUDE_MD_CRATE] {
            let out = render(t, &spec);
            assert!(!out.contains("__"), "unsubstituted token in: {out}");
        }
        let lib = render(LIB_RS, &spec);
        assert!(lib.contains("\"demo_lab::Scale\""));
        assert!(lib.contains("namespace: \"demo_lab\""));
        let cargo = render(CARGO_TOML, &spec);
        assert!(cargo.contains("name = \"demo-lab\""));
        assert!(cargo.contains("/crates/aura-core"));

        // Project-template set (data-only tier, via `render_project`).
        for t in [GITIGNORE_PROJECT, SIGNAL_JSON_STD, CLAUDE_MD_PROJECT] {
            let out = render_project(t, "demo-lab");
            assert!(!out.contains("__"), "unsubstituted token in: {out}");
        }
        let claude = render_project(CLAUDE_MD_PROJECT, "demo-lab");
        assert!(claude.contains("demo-lab"));
        // The CLAUDE.md quickstart targets the closed starter itself through
        // the surviving surface (#319): exec for both document classes, the
        // #246 override residue, and raw-namespace axis discovery (#328).
        assert!(claude.contains("blueprints/signal.json"));
        assert!(claude.contains("--override NODE.PARAM=VALUE"));
        assert!(claude.contains("graph introspect --params"));
    }

    /// #315: the scaffolded project CLAUDE.md teaches the execution semantics
    /// (bias as held target position, protective stop, R) and the document
    /// data plane — the two things the 2026-07-22 field agent had to discover
    /// forensically.
    #[test]
    fn project_claude_md_teaches_execution_semantics_and_the_data_plane() {
        let claude = render_project(CLAUDE_MD_PROJECT, "demo-lab");
        assert!(claude.contains("target position"), "names the held-target model: {claude}");
        assert!(claude.contains("protective stop"), "names the stop that defines R: {claude}");
        assert!(claude.contains("aura process"), "points at the document layer: {claude}");
        assert!(claude.contains("introspect --unwired"), "names the bare-{{}} ramp: {claude}");
    }

    /// #323: the authoring guide's S0 worked literal is byte-identical to the
    /// scaffold's `LIB_RS` template (rendered with the guide's `my_lab`
    /// namespace). The scaffold e2e tests compile that template for real, so
    /// this equality pin is a transitive compile guard — the guide literal
    /// can no longer drift silently from the schema (it broke against the
    /// required `NodeSchema.doc` once).
    #[test]
    fn guide_worked_example_matches_the_scaffold_template() {
        let guide = include_str!("../../../docs/authoring-guide.md");
        let anchor = "### Worked example: `Scale`";
        let after = &guide[guide.find(anchor).expect("guide keeps the S0 worked example")..];
        let start = after.find("```rust\n").expect("worked example is a rust fence") + 8;
        let fence = &after[start..];
        let fence = &fence[..fence.find("\n```").expect("fence closes") + 1];
        let body = &LIB_RS[LIB_RS.find("use aura_core::{").expect("template body starts at the import")..];
        let expected = body.replace("__NS__", "my_lab");
        assert_eq!(
            fence, expected,
            "docs/authoring-guide.md S0 literal drifted from the compiled scaffold template"
        );
    }

    /// Property (#183, fieldtest F2 gap): the scaffold's own starter node teaches
    /// the bound-param build closure. Its rendered `src/lib.rs` declares a param in
    /// the node schema and reads a bound value in the build closure (not the
    /// param-less `|_|` Identity the template shipped before) — the copyable
    /// template content a newcomer learns from directly.
    #[test]
    fn starter_node_declares_and_reads_a_bound_param() {
        let spec = spec_for("demo-lab", None);
        let lib = render(LIB_RS, &spec);
        // the node schema declares a bindable param...
        assert!(
            lib.contains("ParamSpec"),
            "starter node must declare a param in its schema, not `params: vec![]`: {lib}"
        );
        // ...and the build closure reads that bound param (p[0]), not `|_|`.
        assert!(
            lib.contains("p[0].f64()"),
            "starter build closure must consume a bound param (p[0].f64()), not `|_|`: {lib}"
        );
    }

    /// #241: the data-only starter blueprint references std vocabulary only —
    /// no project-namespaced (`::`) type id survives in the rendered JSON.
    /// It binds every param (runnable, #246: bound values are defaults an
    /// `--axis` may override, so this closed starter is also the sweep
    /// target).
    #[test]
    fn data_only_starter_blueprint_is_std_only() {
        let json = render_project(SIGNAL_JSON_STD, "demo-lab");
        assert!(!json.contains("__"), "unsubstituted token: {json}");
        assert!(!json.contains("::"), "project-namespaced id in std-only blueprint: {json}");
        assert!(json.contains("\"name\":\"demo_lab_signal\""));
    }

    #[test]
    fn scaffold_project_refuses_existing_destination() {
        let tmp = std::path::Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/../../target/tmp"))
            .join("aura-pscaf");
        let _ = std::fs::remove_dir_all(&tmp);
        std::fs::create_dir_all(tmp.join("x")).unwrap();
        let spec = project_scaffold_spec("x", &tmp).unwrap();
        let e = scaffold_project(&spec).unwrap_err();
        assert!(e.contains("already exists"), "{e}");
        std::fs::remove_dir_all(&tmp).ok();
    }

    #[test]
    fn scaffold_node_crate_refuses_existing_dir_and_missing_engine() {
        let tmp = std::path::Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/../../target/tmp"))
            .join("aura-scaf");
        let _ = std::fs::remove_dir_all(&tmp);
        std::fs::create_dir_all(&tmp).unwrap();
        // existing destination
        let mut spec = scaffold_spec("x", None, None, &tmp).unwrap();
        std::fs::create_dir_all(tmp.join("x")).unwrap();
        let e = scaffold_node_crate(&spec).unwrap_err();
        assert!(e.contains("already exists"), "{e}");
        // missing engine root
        std::fs::remove_dir_all(tmp.join("x")).unwrap();
        spec.engine_root = PathBuf::from("/nonexistent-engine");
        let e = scaffold_node_crate(&spec).unwrap_err();
        assert!(e.contains("--engine-path"), "{e}");
        std::fs::remove_dir_all(&tmp).ok();
    }
}